perf/fix: port experimental optimizations + focus rework + raidmarkers

Performance optimizations ported from experimental:
- libdebuff: replace 5s startup timer with next-frame defer
- libdebuff: use arg6 auraSlot directly (Nampower 2.29+) instead of GetDebuffSlotMap lookup
- libdebuff: invalidate slotMapCache on PLAYER_TARGET_CHANGED
- nameplates: detect Nampower 2.27.2+ for GUID-based nameplate lookup

Raidmarkers module ported from experimental:
- added raidmarkers.lua
- added config defaults and GUI section
- registered in modules.xml

focus.lua rework:
- removed CastSpellByNameNoQueue (Nampower's CastSpellByName now supports unit tokens/GUIDs natively)
- /focus Name: TargetByName with correct previous target restore + ClearTarget() fallback
- /focus Name: prefix match via SlashCmdList.TARGET when exact match fails
- suppress UI_ERROR_MESSAGE during targeting attempts

swingtimer fixes:
- non-Hunter ranged bar now fills left->right like MH/OH
- fix 1px artifact on Hunter bar center by using Hide() instead of SetWidth(0.1)

modules/nameplates.lua

@@ -2,8 +2,21 @@ pfUI:RegisterModule("nameplates", "vanilla", function ()
   -- disable original castbars
   pcall(SetCVar, "ShowVKeyCastbar", 0)
 
-  -- check for SuperWoW support (use SUPERWOW_VERSION global)
-  local superwow_active = SUPERWOW_VERSION ~= nil
+  -- Check for Nampower support (preferred)
+  local hasNampower = false
+  if GetNampowerVersion then
+    local major, minor, patch = GetNampowerVersion()
+    patch = patch or 0
+    if major > 2 or (major == 2 and minor > 27) or (major == 2 and minor == 27 and patch >= 2) then
+      hasNampower = true
+    end
+  end
+
+  -- Check for SuperWoW support (fallback)
+  local hasSuperwow = SUPERWOW_VERSION ~= nil
+
+  -- Use either Nampower or SuperWoW for GetName(1) GUID support
+  local superwow_active = hasNampower or hasSuperwow
 
   -- Local function references for performance
   local GetTime = GetTime